I'm Bart (from Belgium) and was a member for years allready and now I re-registered after being non-active for a while.I allways wanted to build the HWK with my 4 15"radioshack woofers, never got to it. (I díd build the DB10)Dug up the WinISD program -again- and came to the conclusion that te HWK will play to high with these 4 drivers.If I model the box with only one botom port instead of two, then things look better but still I'm not convinced that these drivers will go lo0Ow enough. :-/I have a DB10, didn't experiment any further than the clamshelled cheapo's but I guess it won't be good enough for low frequency's even with a 100$ speaker?

I want a good sub for HT and music, SPL is not important, just don't want a one-note sub.Is the HWK the way to go anyway?What can I do with these 4 15" radioshack 'things'? ::)

All input is welcome.I'm glad to revisit the forum, it's been too long! 8-)

Re: help on HT and music-sub... PLEASE!Reply #2 - 07/22/07 at 18:32:39

Hey Adrian, I remember you! You also helped me with the DB in "the beginning" lol!Antwerpen isn't far from here, I'm near the coast though, about 30km from the sea.

I would like the sub to go very low... I read, somewhere on this Decware-forum, that music go's as low as 27.5hz and DVD's even lower.That would be very nice of course, but I'm not expecting miracle's...A bit of good low rumbling, that doesn't sound like a one-note sub is what I wish.SPL doesn't matter too much, I'm builing the five surround speaker myself too and those drivers have no high efficiency.

Re: help on HT and music-sub... PLEASE!Reply #3 - 07/23/07 at 08:23:41

Steve mentioned that with the black widow he could go to 40Hz. Thats not HT low but I am thinking that your RS will play lower than the black widow.I have a pair of 12" RS that will do 20hz.For the 15" the HWK or the Imperial is the only way to go without creating your own design. If the HWK does not work you could always keep the box until you can trade up.My 12" DB takes up enough realestate, I cannot imagine having a 15 HWK.

I made a Modded 12" imperial SO and it did not go over well because of the size. Gex

Re: help on HT and music-sub... PLEASE!Reply #4 - 07/23/07 at 08:47:35

Hello Gexter,

One of the all-time posters too! he heIt seems that all the same people stay on the forum, just like a few years ago.A select group! ;D

The Fs is low, 20hz, It's the Vas I'm worried about... 21ft³ !!If it's a dead-born sub (with these drivers) I won't be building the HWK, it's a waste of time, money and space.When clamshelled, they still need 10.5ft³.I know the HWK is a strange working (7th? order) box, but with a lot of simulating in WinISD it seems that it wouldn't go low at all?Could someone ensure me that it will work? Or give directions to change the ports in a way that it fits the RS's?I would love the 4 RS's to be in a HWK and have them thunder away in movie's, just like to know what I can expect, if it stands a chance?

Re: help on HT and music-sub... PLEASE!Reply #5 - 07/23/07 at 15:01:01

only thing you can trust winsd for is calculating port lengths judging by Gex's post, the probably will do good for what you. remember, you can always extend the ports to lower tuning if they won't cut the mustard in the hw, it's time for IB :o[OT]if all goes as planned i'm building a hwk 15 this week[/OT]

Re: help on HT and music-sub... PLEASE!Reply #7 - 07/24/07 at 03:27:24

IBthats an idea, If you have the room for it. the only warning is you may have to equalize it. I love the IB idea and if things were different around here I would have had one long ago because I have the perfect space for it.Go to the infinitelybaffled forum I would go with an array if you can over a manifold, but thats just me.

As far as the HWK goes I cannot tell you for sure it will work and if you only got one shot then maybe do some more research. I can tell you that I consider the HWK a good candidate for large volume drivers as well as the Imperial. ( that does not tell you that its a for sure though)The imperial I built was a SO version of the corner horn imperial and it was bigger than the 15 HWK but mostly by width. I built that one out of cardboard because so many other people did. I wanted to see if a "cardboard speaker worked" and it did.It was laying down under my work bench for a long time before I had to trash it to make room.Good luck!

Re: help on HT and music-sub... PLEASE!Reply #8 - 07/24/07 at 14:50:01

Hi to you too, 60! Another familiar name!

Thanks guy's! I'll have to build something someday, right?!I won't be home the first week to come, but I hope I can use a few of my holiday's, after this week, for this project, just hope that the wife doesn't protest to much...

Re: help on HT and music-sub... PLEASE!Reply #10 - 07/24/07 at 19:08:12

ok, I did some more simulations with WinISD...

When I let the bottom two subs move 'up-down'and the top two, move 'down-up', working against each other,then I'm convinced I can divide the middle chamber by two, because each clamshell needs the same space.So...Then I get two different 4th order band pass enclosures to work with in WinISD.The bottom one gets a peak at about 78.5hz.The top one peaks at ±45hz.If I look at the graphical output and imagine the two plots combined, I get a reasonable flat response.I might just try and draw over it in a graphic program if anyone cares.The only thing I'm not so sure about is, how to combine them correct, example:how much is 92dB + 92dB?is it 95dB?(+3dB) or 98dB?(+6dB) or...?and what about 97dB + 86dB? ::)

I also did a 6th order simulation and didn't take the middle chamber in to account, because that works as a spring, flattening the peaks en dips. Now the two clamshells work the same direction.I'm sure it has more influence than only a spring but I can't use more then what I knowEven with this simulation, it doesn't look that bad either.